Circadian Rhythms
Conditions
Keywords
chronotype, phototherapy, chronotherapy, photoentrainment, light therapy, real-world evidence, patterns of use, circadian medicine
Brief summary
This study looks at how adults use an iPad-based light app in everyday life. Light is the main signal that sets the body's internal clock, which controls daily rhythms in sleep, alertness, and many other body systems. Indoor living means many people do not get bright light at a consistent time each day. The app uses the iPad screen to deliver light while people watch videos, read, or browse. It suggests about one hour of use per day, started within about two hours of waking. It does not require anyone to follow that schedule, and no one is locked out for using it more, less, or at other times. The app shows people when they are positioned to receive the intended light, records how the app is used, and asks short questions about sleep. The main questions this study aims to answer are: 1. How often, how long, and at what time of day do people use the app? 2. What do people mostly do during light-delivery sessions? 3. What do people think of the app, and how easy is it to use? Participants will use the app on an iPad for up to eight weeks, answer short questions about their sleep and how they feel, and share feedback about their experience. Participants may also choose to take part in optional sub-studies. They can wear a device the sponsor provides to record movement, light exposure, and skin temperature, or share data from a wearable device they already use. They can also give blood, saliva, or urine samples, which researchers will use to describe daily patterns in clock-related genes and other markers. These sub-studies are entirely exploratory and voluntary, and participants can take part in the main study without them. Participants will not receive results from any samples they give. This study does not provide medical treatment, and it is not designed to determine whether the app treats or improves any medical condition.
Detailed description
This is a single-site, longitudinal study evaluating how adults use KairOS, an iPad-based light application developed by Circadian OS, Inc., in everyday life for up to eight weeks. Participants are encouraged to use the app for approximately 60 minutes daily within two hours of waking, but use is not enforced. Zero-use stretches, partial weeks, and re-engagement after a gap are recorded as participation data rather than protocol deviations. App telemetry, sleep logs, and participant feedback are used to characterize patterns of use and overall usability. Participants may also opt into an exploratory biomarker sub-study involving collection of blood, saliva, or urine samples; no laboratory results are returned to participants. Other optional activities include actigraphy, light-exposure monitoring, and moderated task-observation sessions.
Interventions
DEVICECircadian OS iPad-based light app
Software-based light-delivery platform running on an off-the-shelf iPad. The app uses the display to deliver light targeting a specified circadian stimulus (CS ≥ 0.3), integrating spectrum and intensity at the eye. It runs closed-loop: screen luminance is calibrated in advance, the iPad camera tracks viewing distance and gaze direction, and the app computes the dose reaching the eye in real time, signaling whether the user is positioned to receive it. Session start-time recommendations are anchored to each participant's habitual wake time, derived from the Munich ChronoType Questionnaire. Onboarding presents a recommended envelope of approximately 60 minutes per day within approximately 2 hours of habitual wake. Use is not enforced and the app does not lock out off-envelope use. Participants use the app while streaming, reading, or browsing as they normally would.
Sponsors
Circadian OS, Inc
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
OTHER
Masking
NONE
Intervention model description
Single-arm, open-label, naturalistic device-use study. All participants receive the investigational app and use it without enforcement or lockout. Adherence to the recommended use envelope is not required, and non-use, partial weeks, and re-engagement are recorded as participation data rather than protocol deviations. Optional sub-studies (actigraphy, biomarker collection, moderated human-factors sessions) are independently elected by participants and do not constitute separate assigned arms.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Adult 18 years of age or older * Able to read, understand, and provide written informed consent in English * Has access to a compatible iPad capable of running the study app for the duration of the exposure period, or is willing to use a Sponsor-supplied iPad * U.S. resident, able to be in the NYC metropolitan area for the study * Member of the Sponsor's network (friends, family, advisors, investors, employees, or contractors) * If opting in to the biomarker sub-study: weighs at least 110 lb (50 kg), and meets standard venipuncture eligibility on the day of collection
Exclusion criteria
* Diagnosed bipolar disorder, or history of light-induced manic or hypomanic episodes * Pregnant, attempting to become pregnant, or breastfeeding * Diagnosed photosensitivity disorder, retinal disease, or use of medications known to cause significant photosensitivity, at investigator discretion based on disclosed medications * Currently using prescription light therapy, or actively enrolled in another light-related research study * Unable to consent for themselves (participants requiring enrollment by a legally authorized representative are not eligible) * Biomarker sub-study only: acutely unwell, febrile, or reporting acute infectious symptoms on the study day * Biomarker sub-study only: known bleeding diathesis, anticoagulant use other than low-dose aspirin, severe needle phobia, or whole-blood or plasma donation within the prior two weeks * Biomarker sub-study only: member of the study or laboratory team who would otherwise process their own sample * Any condition that, in the judgment of the investigator or attending phlebotomist or nurse, would make participation unsafe
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Frequency of Circadian OS app (KairOS) use | From initiation of app use through the end of the app-exposure period, up to eight weeks | Number of light-delivery sessions completed per participant per week, captured by in-app telemetry. |
| Duration of app use: minutes of light exposure per session | From initiation of app use through the end of the app-exposure period, up to eight weeks | Duration in minutes of each light-delivery session, captured by in-app telemetry. |
| Timing of app use relative to habitual wake time | From initiation of app use through the end of the app-exposure period, up to eight weeks | Start time of each light-delivery session, expressed as hours elapsed since the participant's habitual wake time, as measured by the Munich Chronotype Questionnaire completed at baseline. |
| Context of app use | From initiation of app use through the end of the app-exposure period, up to eight weeks | Concurrent on-screen activity during light-delivery sessions, captured by in-app telemetry. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Participant-reported feedback on the app experience, usability, and perceived effects | Weekly during the app-exposure period and at the end of the app-exposure period, up to eight weeks | Structured and free-text participant feedback on the app experience, usability, and perceived effects, including the Perceived Effects Scale (Compared to Before the Study), a study-specific 5-point Likert measure (range 1-5, higher scores indicate a better perceived outcome; 1 = Much worse, 2 = Somewhat worse, 3 = No change, 4 = Somewhat better, 5 = Much better). |
| Self-reported sleep and circadian-rhythm parameters during the exposure period | From initiation of app use through the end of the app-exposure period, up to eight weeks | Participant-reported sleep parameters captured through an in-app daily sleep log during the exposure period, including bedtime, wake time, nighttime awakenings, napping, and sleep quality. Weekly participant check-ins capture sleep quality and daytime alertness relative to usual. |
| Drop-off and return-to-use patterns | From initiation of app use through the end of the app-exposure period, up to eight weeks | Consecutive zero-use days per participant, partial weeks of use, and re-engagement events following a use gap. |
| System Usability Scale (SUS) score | End of Week 1 and end of the app-exposure period; a single administration is done at the end of Week 1 when the app-exposure period is one week | Participant-completed 10-item System Usability Scale, scored 0-100, with higher scores indicating better perceived usability. |
| Number of Use Errors Identified During App Use | From initiation of app use through the end of the app-exposure period, up to eight weeks | Use errors identified from in-app telemetry and participant-reported problems, documented with description and frequency. |
| Root-Cause Category of Identified Use Errors | From initiation of app use through the end of the app-exposure period, up to eight weeks | Identified use errors are categorized by root cause (perception, cognition, or action) per human-factors methodology, based on in-app telemetry and participant-reported problems. |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORSofia Axelrod, PhD
Circadian OS, Inc
Outcome results
None listed